Imaging system

Abstract

It is disclosed an imaging system comprising: radiation generating means including at least one radiation source for generating radiations; data acquiring means including an detector matrix faced the radiation source for obtaining projection data by receiving radiations penetrated through an object to be inspected; transporting means for making the object to be inspected between the radiation source and the detector matrix linearly moving relative to the radiation source and the detector matrix; and controlling and image processing means for controlling the radiation generating means, the data acquiring means and the transporting means, and for reconstructing an image of the object to be inspected from the projection data. The imaging system according to the present invention achieves a real stereoscopic radiography by using straight-line trajectory scan and reconstructing a tomographic or stereoscopic image through a straight-line filtered back-projection algorithm. The present imaging system has advantages of fast examination speed, no rotation, and out of large cone-angle problem in a circular-orbit cone-beam CT.

1. An imaging system comprising:
 radiation generating means including at least one radiation source for generating radiations;
 data acquiring means including a detector matrix opposite to the radiation source for obtaining projection data by receiving radiations penetrated through an object to be inspected; 
 transporting means for making the object to be inspected between the radiation source and the detector matrix linearly moving relative to the radiation source and the detector matrix; and 
 controlling and image processing means for controlling the radiation generating means, the data acquiring means and the transporting means, and for reconstructing an image of the object to be inspected from the projection data; 
 wherein the controlling and image processing means includes: 
 a projection data conversion section for converting the projection data into projection data under quasi-parallel-beam scan; 
 a filtration section for obtaining filtered projection data by convoluting the projection data under quasi-parallel-beam scan with a predetermined convolutional kernel; and 
 a back-projection section for reconstructing the image by back-projecting the filtered projection data with a weighting factor; 
 wherein the imaging system uses straight-line trajectory scan and straight-line filtered back projection, in which the filter section one-dimensionally convolutes the projection data in the direction of the line along which the object to be inspected is moving, and the back-projection section back-projects the filtered projection data in the direction of radiation projection. 
 
 
   
   
     2. The imaging system according to  claim 1 , wherein the plurality of detector elements are equi-distantly arranged. 
   
   
     3. The imaging system according to  claim 2 , wherein
 the projection data conversion section reverses and shifts the projection data p(l,t,z) to obtain the projection data q(l,t,z) under quasi-parallel-beam scan, wherein the projection data p(l,t,z) denotes a projection value at a coordinate of t in the z th  slice of the detector when the object to be inspected relatively moves to a coordinate of l on the line; 
 the filtration section one-dimension convolutes the projection data q(l,t,z) under quasi-parallel-beam scan with the predetermined convolutional kernel in the l direction to obtain the filtered projection data Q(l′,t,z); and 
 the back-projection section back-projects the filtered projection data Q(l′,t,z) along the radiation projection direction a weighting factor to obtain the reconstructed image. 
 
   
   
     4. The imaging system according to  claim 1 , wherein the plurality of detector elements are equi-angularly arranged. 
   
   
     5. The imaging system according to  claim 4 , wherein
 the projection data conversion section reverses and shifts the projection data p(l,γ,z) to obtain the projection data q(l,γ,z) under quasi-parallel-beam scan, wherein the projection data p(l,γ,z) denotes a projection value at an angular position of γin the z th  slice of the detector matrix when the object to be inspected relatively moves to a coordinate of l on the line; 
 the filtration section one-dimension convolutes the projection data q(l,γ,z) under quasi-parallel-beam scan with the predetermined convolutional kernel in the l direction to obtain the filtered projection data Q(l′,γ,z); and 
 the back-projection section back-projects the filtered projection data Q(l′,γ,z) with along the radiation projection direction a weighting factor to obtain the reconstructed image. 
 
   
   
     6. The imaging system according to  claim 1 , wherein the plurality of detector elements are solid detector elements, gas detector elements or semiconductor detector elements. 
   
   
     7. The imaging system according to  claim 1 , wherein the radiation source is an X-ray accelerator, an X-ray tube or a radioisotope. 
   
   
     8. The imaging system according to  claim 1 , wherein a horizontal range of projection angles is more than 90 degree. 
   
   
     9. The imaging system according to  claim 8 , wherein the detector matrix comprises a plannar detector containing a plurality of detector elements. 
   
   
     10. The imaging system according to  claim 8 , wherein the detector matrix comprises a collinear detector provided vertically and containing a plurality of detector elements. 
   
   
     11. The imaging system according to  claim 10 , wherein the detector matrix further comprises another collinear detector provided horizontally and containing a plurality of detector elements. 
   
   
     12. The imaging system according to  claim 11 , wherein the another collinear detector horizontally provided has a variable position in the vertical direction.